On 09/09/2025 11:21, David Hildenbrand wrote:

On 09.09.25 04:16, Andrew Morton wrote:

quoted

On Mon,  8 Sep 2025 08:39:24 +0100 Kevin Brodsky
[off-list ref] wrote:

quoted

The main change enabling nesting is patch 2, following the approach
suggested by Catalin Marinas [4]: have enter() return some state and
the matching leave() take that state.

This is so totally the correct way.  Thanks.

Staring at this, I wonder if we could alternatively handle it like
pagefault_disable()/pagefault_enable(), having something like
current->lazy_mmu_enabled.

We wouldn't have to worry about preemption in that case I guess
(unless the arch has special requirements).

Not sure if that was already discussed, just a thought. 

That's an interesting point, I think I've addressed it in reply to patch
2 [1].

- Kevin

[1]
https://lore.kernel.org/all/47ee1df7-1602-4200-af94-475f84ca8d80@arm.com/ (local)